Quercetin Health Benefits, Properties, and Uses

What is Quercetin?

Quercetin is a type of plant pigment belonging to a group called flavonoids, which give fruits, vegetables, and flowers their colors. It’s naturally found in onions, berries, apples, tomatoes, broccoli, asparagus, buckwheat, and red wine. It can also be taken as a supplement. These supplements are available in capsule, pill, or powder form. Quercetin is sometimes packaged with the enzyme bromelain since both act as anti-inflammatories. It also pairs well with vitamin C since flavonoids like quercetin help enhance vitamin C.1,2,3

Quercetin Uses and Health Benefits

Quercetin benefits many body processes. Flavonoids like quercetin act as antioxidants, which means they neutralize free radicals, which are particles in the body that can damage DNA and cell membranes. This makes quercetin effective in protection against cancer and heart disease.1 It’s also said to combat hypertension, strengthen capillaries to reduce bruising, and improve circulation.5,6,7 Other quercetin uses include for high cholesterol and interstitial cystitis. Some athletes take quercetin supplements to increase exercise endurance.1,2 A quercetin diet can also help with the following conditions:

Prostatitis - Quercetin is highly effective at treating prostatitis and has been shown to reduce pain and inflammation associated with the condition.

Allergy (Allergies) - Among quercetin benefits, it acts as an antihistamine. Histamines are chemicals in the body that cause allergic reactions. Therefore, quercetin can help reduce those reactions. It helps in treating seasonal allergies, or hay fever, when taken for six to eight weeks.

Arthritis - Quercetin acts as an anti-inflammatory, which can help reduce the pain and symptoms associated with arthritis.

Asthma - Among quercetin benefits, it’s said to support healthy bronchial passages, which can strengthen lungs and improve asthma. It also inhibits lipoxygenase, which is an enzyme that causes asthma problems.

Breast Cancer - Quercetin uses include using it to treat and reduce the risk of cancer. Studies have even shown that flavonoids like quercetin can inhibit the growth of breast cancer cells.

Quercetin Side Effects and Precautions

Quercetin is considered safe, but dosage amounts vary depending on the person and condition being treated. Quercetin side effects can include upset stomach and headache. In high doses, defined as over one gram per day, it can cause kidney damage and loss of protein function. Recommended doses start at 100 to 250 mg three times per day, with up to 400 mg twice daily to combat hay fever. Take quercetin sparingly with breaks between doses. Do not take quercetin supplements if you are pregnant or breastfeeding or have kidney disease.1,2

Quercetin may interact with certain herbs and medications, including antibiotics and anticoagulants.1 It also interacts with enzymes that break down felodipine. Avoid quercetin supplements if you’re taking felodipine. Quercetin can also change estrogen metabolism in human liver cells, which increases estradiol levels and reduces other estrogen levels in the body.3 Talk to your doctor about using a quercetin supplement before attempting to self-medicate.